The reaction products of sulfur with polythiol compositions are well known. The character of said products can be varied from a soft, rubber-like composition to a hard, tough, resilient material by varying proportions of polythiol to sulfur. The reaction can be carried out between ambient temperatures and temperatures up to about 200.degree.C. A basic catalyst is generally utilized to reduce reaction time.
The properties of polythiol-sulfur reaction products are unpredictable as they depend upon the temperature of the reaction, the reaction time, the amount of catalyst used, the concentration of the polythiol, the nature of the polythiol, and the temperature history of the reaction mixture.
As disclosed in U.S. Pat. No. 3,434,852, in order to provide material within a useful viscosity range, it is the custom to introduce viscosity improving or viscosity reducing agents into the plasticized sulfur composition.
Whenever a polythiol-sulfur composition is heated, the properties of the composition change. Viscosity improvers can be added to the plasticized sulfur composition to compensate for the increase in viscosity which accompanies heating of polythiol-sulfur reaction products. The viscosity of molten polythiol sulfur reaction compositions are stabilized by introducing monomercaptans into the reaction mixture along with the polythiols.
Reaction products of sulfur and polythiols and their methods of preparation are disclosed in U.S. Pat. Nos. 3,434,852, 3,734,753 and 3,453,126 and British Pat. No. 1,303,832.
It is an object of the present invention to provide a method of stabilizing the polythiol-sulfur reaction mixture so that the characteristics of said mixture do not change with subsequent heating and cooling of the product. It is a further object of the present invention to provide a method of stabilizing the viscosity of polythiol-sulfur reaction mixtures.